JP2008045637A - Controller for vehicular automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a vehicular automatic transmission capable of continuously carrying out control by both of a speed change control means 130 and a hill climbing and descending speed change control means 134 by prohibiting transition to a high speed stage of an automatic transmission 16, in a situation that the finish of control by the speed change control means (a constant speed travel control means) 130 and the starting of control by the hill climbing and descending speed change control means 134 should be carried out at the same time. <P>SOLUTION: A gradient value calculating means 140 is provided for calculating a value relevant to a gradient of a road surface by using a value of a vehicle traveling state, a brake operation determining means 144 is provided for determining the existence or nonexistence of brake operation, and a hill climbing and descending speed change executing means 136 is provided for outputting a value relevant to the road surface gradient immediately before brake operation determination to the hill climbing and descending speed change control means 134 and executing hill climbing and descending speed change control when it is determined that there is brake operation during speed change control by the speed change control means 130. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission of a vehicle, and more particularly to a control device for an automatic transmission including both a shift control means and an uphill / downhill shift control means.

  2. Description of the Related Art A control device for an automatic transmission that includes a shift control unit that prohibits the gear ratio of the automatic transmission from becoming higher than a predetermined gear ratio is widely used. For example, this is the control of an automatic transmission called cruise control. In cruise control, in order to keep the vehicle running at a constant speed, in addition to controlling the throttle opening, the use of some high-speed stages of the automatic transmission to prevent shortage of driving force The automatic transmission is controlled so as to prohibit the transmission. When an operation of a service brake for braking the vehicle (hereinafter simply referred to as “brake operation”) is performed, it is considered that the driver intends to decelerate, and the automatic transmission control means performs the automatic operation. Transmission control is immediately terminated.

  On the other hand, uphill / downhill shift control is performed in which the road surface gradient is calculated using the value of the running state of the vehicle and the shift ratio of the automatic transmission is prohibited from shifting to the high speed side based on the calculated value regarding the road surface gradient. For example, the invention described in Patent Document 1 is such that when the road surface has a large gradient, the shift to the upshift side (high speed side) is suppressed. In such uphill / downhill shift control, for example, when the vehicle is traveling on a downward slope, the automatic transmission is configured to prohibit the use of some high-speed stages of the automatic transmission with the brake operation by the driver as a start condition. Downhill shift control for controlling is performed. That is, since the brake operation by the driver is the intention of deceleration, the automatic transmission is controlled so as to prohibit the use of some high speed stages of the automatic transmission because the engine brakes decelerate.

Japanese Patent Laid-Open No. 7-332445

  Here, for the uphill / downhill shift control, it is necessary to grasp the gradient of the road surface on which the vehicle travels. In Patent Document 1, the tire radius, the vehicle mass, the vehicle acceleration, the rolling resistance and the air resistance, It can be calculated from the value of the output torque. However, although this method is effective when the vehicle is accelerating or traveling at a constant speed, the acceleration of the vehicle is not necessarily the power provided by the engine of the vehicle during the deceleration of the vehicle by the driver's braking operation. There is a problem that the slope of the road surface cannot be calculated correctly because it is not only the influence of gravity in the road.

  By the way, both the above-described shift control means and the uphill / downhill shift control means execute control by prohibiting the use of some high speed stages of the automatic transmission. Both can be provided. However, the purpose of these shift control means and uphill / downhill shift control means is to maintain the vehicle speed of the shift control means, while that of the uphill / downhill shift control means is for obtaining an optimum engine brake. However, since they are different from each other, it is necessary to prevent their actions from interfering with each other. Therefore, the other control is not executed while the control by one means is being executed.

  FIG. 10 shows a case where a vehicle having an automatic transmission control device equipped with both the shift control means and the uphill / downhill shift control means travels on a downhill road surface by the shift control means. 5 is a timing chart showing a state in which the control by the shift control means is terminated due to a brake operation performed by a person and the control shifts to the control by the uphill / downhill shift control means. Hereinafter, description will be given with reference to this timing chart. In the figure, the numbers surrounded by circles represent changes in the gear positions used.

  In the automatic transmission control device including both the shift control means and the uphill / downhill shift control means, for example, when the vehicle is traveling on a downhill road surface by the shift control means (t1 to t3). ) When a brake operation is performed by the driver, the control by the shift control means is terminated (t3). On the other hand, it is detected that the vehicle is traveling on a down-gradient road surface, which is a condition for executing the uphill / downhill shift control means, and that the brake operation has been performed, and the control by the shift control means is completed. Therefore, the uphill / downhill shift control should be started simultaneously with the end of the shift control means. However, as described above, since the uphill / downhill shift control means is not executed during the execution of the shift control means (t1 to t3), the road gradient is calculated by the end of the shift control means (t3). In addition, the brake operation is performed by the driver at the end of the shift control means (t3), and the road surface gradient is correctly calculated while the vehicle is decelerating by the brake operation (t3 to t4). Therefore, since it is not determined that the slope has a downward slope, there is a problem that the control by the uphill / downhill shift control means is not started.

  Further, when the brake operation by the driver is released (t4) and the uphill / downhill shift control means is started (t5), some of the high speed stages (for example, the fifth to sixth speed stages) of the automatic transmission are started. Use is prohibited. As described above, during the control by the shift control means (t2 to t3), the use of some high speed gears (for example, the fourth to sixth gears) of the automatic transmission is prohibited, while the shift After the control by the control means is completed and before the control by the uphill / downhill shift control means is started (t3 to t5), all the shift speeds (for example, first to sixth speed stages) of the automatic transmission are used. Is not prohibited. Therefore, with the end of the control by the shift control means (t3), the shift stage of the automatic transmission changes to the high speed side that has been prohibited until then (from the third speed to the sixth speed), and thereafter With the start of the control by the uphill / downhill shift control means (t5), the use of the high speed side shift stage of the automatic transmission is prohibited and the shift stage is changed to the low speed side (6th speed → 4th speed). Stage), there is a problem that hunting of the gear ratio occurs.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a control device for an automatic transmission that includes both a shift control means and an uphill / downhill shift control means, and is controlled by the shift control means. Of the automatic transmission that prohibits the shift of the automatic transmission to the high speed stage and can perform the control by both means continuously in the situation where the end of the control and the start of the control by the uphill / downhill control transmission means should be made at the same time To provide an apparatus.

  The gist of the present invention for solving this problem is that (a) the transmission ratio of the automatic transmission is prohibited from being higher than the predetermined transmission ratio, and the control is released if there is a regular brake operation. And (b) an uphill / downhill shift control means for prohibiting the speed ratio of the automatic transmission from becoming higher than a predetermined speed ratio based on a value relating to the slope of the road surface during traveling on the uphill / downhill road. In the control device for an automatic transmission for a vehicle, (c) a gradient value calculating means for calculating a value related to the road surface gradient; (d) a brake operation determining means for determining whether or not the brake operation is performed; When shift control is being performed by the control means and the brake operation is determined by the brake operation determination means, a value related to the road surface gradient immediately before the brake operation determination is output to the uphill / downhill shift control means, and the uphill / downhill shift And characterized by providing the uphill slope shift execution means for executing the control.

  In this way, in the automatic transmission, even after the shift control is canceled by the brake operation while traveling on the uphill / downhill road, the uphill / downhill shift control is performed using the value related to the road gradient immediately before the brake operation. In addition, it is possible to smoothly shift to the uphill / downhill shift control and to continuously perform the control for prohibiting the shift of the gear ratio to the high speed side, so that the hunting of the gear ratio can be prevented.

  Here, preferably, the speed change control means is a constant speed running control means for controlling a gear ratio of the automatic transmission so as to maintain a constant speed running of the vehicle.

  In this way, even when the control by the uphill / downhill shift control means is performed immediately after the control by the constant speed travel control means for constant speed travel is canceled by the brake operation, the uphill / downhill shift control is smoothly performed. Since the shift can be performed and the control for prohibiting the shift of the gear ratio to the high speed side can be continuously performed, the hunting of the gear ratio can be prevented.

  Preferably, the uphill / downhill shift control means prohibits the shift ratio of the automatic transmission from being higher than a predetermined shift ratio based on a value relating to the gradient of the road surface, particularly when traveling on a downhill road. It is a shift control means.

  In this way, on the downhill road where the brake operation by the driver corresponds to both the operation for releasing the control by the shift control means and the operation for starting the control by the downhill shift control means. Even immediately after releasing the shift control by brake operation while traveling downhill, the downhill shift control is performed using the value related to the road surface gradient immediately before the brake operation, so it is possible to smoothly shift to the downhill shift control after the brake operation, Since control for prohibiting the shift of the gear ratio to the high speed side can be continuously performed, hunting of the gear ratio can be prevented.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating the configuration of a vehicle power transmission device 10 to which the present invention is applied. In FIG. 1, for example, an output of an engine 12 as a driving power source for traveling constituted by an internal combustion engine is input to an automatic transmission 16 via a torque converter 14 as a fluid power transmission device, and a differential (not shown) It is transmitted to the drive wheel via a gear device and an axle. The torque converter 14 includes a pump impeller 20 connected to the engine 12, a turbine impeller 24 connected to the input shaft 22 of the automatic transmission 16, and a stator that is prevented from rotating in one direction by a one-way clutch 28. The impeller 30 is provided, and power is transmitted between the pump impeller 20 and the turbine impeller 24 via a fluid, and the lockup for directly connecting the pump impeller 20 and the turbine impeller 24 is performed. A clutch 26 is provided. The lock-up clutch 26 is a hydraulic friction clutch that is frictionally engaged by a differential pressure ΔP between the hydraulic pressure in the engagement-side oil chamber 32 and the hydraulic pressure in the release-side oil chamber 34, and is fully engaged. Thus, the pump impeller 20 and the turbine impeller 24 are rotated together. Further, the differential pressure ΔP, that is, the engagement torque is feedback-controlled so as to engage in a predetermined slip state, so that the turbine impeller 24 is pumped with a predetermined slip amount of, for example, about 50 rpm when the vehicle is driven (power-on). While following and rotating with respect to the impeller 20, the pump impeller 20 is caused to follow and rotate with respect to the turbine impeller 24 with a predetermined slip amount of about −50 rpm, for example, when the vehicle is not driven (power off).

  The automatic transmission 16 is a planetary gear type transmission that includes a first planetary gear device 40 of a double pinion type, a second planetary gear device 42 of a single pinion type, and a third planetary gear device 44. The sun gear S1 of the gear device 40 is selectively connected to the input shaft 22 via the clutch C3, and is selectively connected to the housing 38 via the one-way clutch F2 and the brake B3. Rotation in the opposite direction) is prevented. The carrier CA1 of the first planetary gear unit 40 is selectively connected to the housing 38 via the brake B1, and is always prevented from rotating in the reverse direction by the one-way clutch F1 provided in parallel with the brake B1. It has become so. The ring gear R1 of the first planetary gear device 40 is integrally connected to the ring gear R2 of the second planetary gear device 42, and is selectively connected to the housing 38 via the brake B2. The sun gear S2 of the second planetary gear device 42 is integrally connected to the sun gear S3 of the third planetary gear device 44, is selectively connected to the input shaft 22 via the clutch C4, and the one-way clutch F0. Further, it is selectively connected to the input shaft 22 via the clutch C1, and is prevented from rotating in the opposite direction relative to the input shaft 22. The carrier CA2 of the second planetary gear unit 42 is integrally connected to the ring gear R3 of the third planetary gear unit 44, and is selectively connected to the input shaft 22 via the clutch C2 and via the brake B4. The housing 38 is selectively connected to the housing 38, and the one-way clutch F3 provided in parallel with the brake B4 is always prevented from rotating in the reverse direction. The carrier CA3 of the third planetary gear device 44 is integrally connected to the output shaft 46.

  The clutches C1 to C4 and the brakes B1 to B4 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic friction engagement devices that are controlled by a hydraulic actuator such as a multi-plate clutch or brake. Thus, when the hydraulic circuit is switched by the solenoid valves Sol1 to Sol5 and the linear solenoid valves SL1 and SL2 of the hydraulic control circuit 98 (see FIG. 3) and the manual valves (not shown), for example, as shown in FIG. The engagement and release states are switched to each other, and six forward speeds (1st to 6th) and one reverse speed (Rev) are established according to the operation position (position) of the shift lever 72 (see FIG. 4). . In FIG. 2, “1st” to “6th” mean the first to sixth forward speeds, and the gear ratio γ () increases from the first gear “1st” to the sixth speed “6th”. = Rotational speed NIN of the input shaft 22 / rotational speed NOUT of the output shaft 46) is small, and the gear ratio of the fourth gear stage "4th" is 1.0. In FIG. 2, “◯” represents engagement, blank represents release, “(◯)” represents engagement during engine braking, and “●” represents engagement not involved in power transmission.

  The hydraulic control circuit 98 shown in FIG. 3 mainly includes the above-described shift solenoid valves Sol1 to Sol5, linear solenoid valves SL1 and SL2, and lockup hydraulic pressure, that is, the hydraulic pressure in the engagement side oil chamber 32 and the release side oil chamber. 34 includes a linear solenoid valve SLU that controls a differential pressure ΔP with respect to the hydraulic pressure in 34, and a linear solenoid valve SLT that mainly controls the line hydraulic pressure. The hydraulic oil in the hydraulic control circuit 98 is also supplied to the lockup clutch 26. At the same time, it is also used for lubricating each part of the automatic transmission 16 and the like.

  FIG. 3 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 12 and the automatic transmission 16 of FIG. 1, and the accelerator opening Acc, which is the operation amount of the accelerator pedal 50, is shown in FIG. It is detected by the degree sensor 51. The accelerator pedal 50 is largely depressed according to the driver's required output amount, and corresponds to an accelerator operation member, and the accelerator opening Acc corresponds to the required output amount. The intake pipe of the engine 12 is provided with an electronic throttle valve 56 that is opened by the throttle actuator 54 according to the accelerator opening Acc, that is, the throttle opening θTH. An ISC that controls the intake air amount when the electronic throttle valve 56 is fully closed is provided in a bypass passage 52 that bypasses the electronic throttle valve 56 for idle rotation speed control in order to control the idle rotation speed NEIDL of the engine 12. (Idle rotation speed control) A valve 53 is provided. In addition, an engine speed sensor 58 for detecting the rotational speed NE of the engine 12, an intake air quantity sensor 60 for detecting the intake air quantity Q of the engine 12, and intake air for detecting the temperature TA of the intake air. Temperature sensor 62, electronic throttle valve 56 fully closed (idle state) and throttle sensor 64 with idle switch for detecting its throttle opening θTH, vehicle speed V (corresponding to rotational speed NOUT of output shaft 46) are detected. A vehicle speed sensor 66 for detecting the engine temperature, a coolant temperature sensor 68 for detecting the coolant temperature TW of the engine 12, a brake switch 70 for detecting whether or not the foot brake pedal 69, which is a service brake, is operated, and a lever position of the shift lever 72 (Operating position) Lever position sensor 74 for detecting PSH, turbine rotation speed Turbine rotational speed sensor 76 for detecting NT (= rotational speed NIN of input shaft 22), AT oil temperature sensor 78 for detecting AT oil temperature TOIL which is the temperature of hydraulic oil in hydraulic control circuit 98, up A shift switch 80, a downshift switch 82, a cruise control switch 132, and the like are provided. From these sensors and switches, the engine speed NE, the intake air amount Q, the intake air temperature TA, the throttle opening θTH, the vehicle speed V, Engine cooling water temperature TW, presence or absence of brake operation, lever position PSH of shift lever 72, turbine rotational speed NT, AT oil temperature TOIL, shift range up command RUP, down command RDN, cruise control switch 132 main switch ON state Signal indicating the vehicle speed set switch of the cruise control switch 132 A vehicle speed set signal indicating the ON operation CSET Ji, so that the signal representative of such cancellation signal preset vehicle speed VT representing the ON operation CCAN the release switch of the cruise control switch 132 is supplied to the electronic control unit 90. Further, it is connected to an ABS (anti-lock brake system) 84 for controlling the braking force so that the wheel is not locked (slip) when the foot brake pedal 69 is operated, so that information relating to the brake hydraulic pressure corresponding to the braking force is supplied. It has become.

  The electronic control unit 90 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM, and signals according to a program stored in the ROM in advance. By performing processing, output control of the engine 12, shift control of the automatic transmission 16, lockup clutch control of the lockup clutch 26, and the like are executed. For engine control and shift control as necessary. It is divided into and.

  Regarding the output control of the engine 12, in addition to controlling the opening and closing of the electronic throttle valve 56 by the throttle actuator 54, the fuel injection valve 92 is controlled for controlling the fuel injection amount, and the ignition device 94 such as an igniter is used for controlling the ignition timing. And the ISC valve 53 is controlled for idle rotation speed control. The electronic throttle valve 56 is controlled by, for example, driving the throttle actuator 54 based on the actual accelerator opening Acc from the relationship shown in FIG. 5, and increasing the throttle opening θTH as the accelerator opening Acc increases. When the engine 12 is started, the crankshaft 18 of the engine 12 is cranked by the starter (electric motor) 96.

  For the shift control of the automatic transmission 14, for example, a pre-stored shift diagram (shift map) shown in FIG. 6 is selected according to the lever position PSH of the shift lever 72 shown in FIG. From the diagram, based on the actual throttle opening θTH and the vehicle speed V, the gear stage to be shifted of the automatic transmission 16 is determined, that is, the shift determination from the current gear stage to the shift destination gear stage is executed, and the determination is made. The shift output for starting the shift operation to the selected gear stage is executed. The shift lever 72 is disposed in the vicinity of the driver's seat and is manually operated to four lever positions “R (reverse)”, “N (neutral)”, “D (drive)”, or “S (sequential)”. It is like that. The “R” position is the reverse travel position, the “N” position is the power transmission cut-off position, the “D” position is the forward travel position by automatic shifting, and the “S” position is a plurality of gears on the high-speed side that can be shifted. The lever position sensor 74 detects which lever position the shift lever 72 is operated at, which is a forward travel position where manual shift is possible by switching the shift range. The lever positions “R”, “N”, and “D (S)” are provided along the front-rear direction of the vehicle (the upper side in FIG. 4 is the front side of the vehicle), and the shift lever 72 is connected via a cable or a link. The manual valve connected in this manner is mechanically operated in accordance with the forward / backward operation of the shift lever 72 so that the hydraulic circuit is switched. In the “R” position, the reverse circuit is mechanically established. 2 is established, and the reverse gear stage “Rev” shown in FIG. 2 is established. At the “N” position, the neutral circuit is established mechanically and all the clutches C and brakes B are released.

  Further, when operated to the “D” position or “S” position, which is the forward travel position, the hydraulic circuit is switched by the manual valve according to the operation of the shift lever 72, and the forward circuit is mechanically established. Thus, the vehicle can travel forward while shifting at the first shift speed “1st” to the sixth shift speed “6th”, which are the forward shift speeds. When the shift lever 72 is operated to the “D” position, this is judged from the signal of the lever position sensor 74 and the automatic shift mode is established, and the first shift stage “1st” to the sixth shift stage “6th” are established. Shift control is performed using all of the forward shift speeds. That is, the solenoid valves Sol1 to Sol5 and the linear solenoid valves SL1 and SL2 are energized and de-energized so that a shift shock such as a change in driving force does not occur and the durability of the friction material is not impaired. By controlling, the hydraulic control circuit 98 is switched to establish one of the forward shift speeds from the first shift speed “1st” to the sixth shift speed “6th”. The solid line in FIG. 6 is the upshift line, and the broken line is the downshift line, and the gear ratio (= input rotational speed NIN / output rotational speed NOUT) as the vehicle speed V decreases or the throttle valve opening θTH increases. Is switched to a low-speed side gear stage, and “1” to “6” in the figure mean the first speed gear stage “1st” to the sixth speed gear stage “6th”. Note that, in the first gear stage “1st” to the fourth gear stage “4th”, each gear stage is established by engaging the one-way clutches F0 to F3. In order to obtain the engine braking action, the clutch C or the brake B (hereinafter referred to as engine brake element) corresponding to “(◯)” shown in FIG. 2 is engaged. By obtaining an engine braking action when the vehicle is decelerating, the braking force of the vehicle is increased. On the other hand, when the vehicle is in the neutral state, the drive wheel (not shown) and the input shaft 22 are separated from each other together with the turbine rotational speed NT. The fuel cut state by the fuel cut device is continued for as long as possible so that the engine speed NE is not temporarily reduced, and the fuel efficiency effect by the fuel cut is obtained.

  When the shift lever 72 is operated to the “S” position, this is judged from the signal of the lever position sensor 74 and the manual shift mode is established. The “S” position is provided adjacent to the width direction of the vehicle at the same position as the “D” position in the longitudinal direction of the vehicle, and the hydraulic circuit is the same as in the “D” position. The manual shift mode in which a plurality of shift ranges determined within the shift range in which the gears can be shifted at the position, that is, between the first shift stage “1st” and the sixth shift stage “6th” can be arbitrarily selected is electrically established. is there. In the “S” position, an upshift position “(+)” and a downshift position “(−)” are provided in the front-rear direction of the vehicle, and the shift lever 72 is moved to the upshift position “(+)”. ”Or downshift position“ (−) ”is detected by the upshift switch 80 and downshift switch 82, and the maximum speed, that is, the high speed ratio with a small gear ratio is determined in accordance with the up command RUP and the down command RDN. One of the six shift ranges “D”, “5”, “4”, “3”, “2”, “L” with different shift ranges on the side is electrically established, and within each shift range, for example, Shift control is automatically performed according to the shift map of FIG. The upshift position “(+)” and the downshift position “(−)” are both unstable, and the shift lever 72 is automatically returned to the “S” position by a biasing means such as a spring. Therefore, the shift range is changed according to the number of operations or the holding time for the upshift position “(+)” or the downshift position “(−)”.

  FIG. 7 is a functional block diagram for explaining a main part of the control function of the control device of the automatic transmission 16 provided in the electronic control device 90. In FIG. 7, the control device for the automatic transmission 16 is roughly divided into a cruise control unit and a shift control unit in terms of functions. The cruise control unit includes a constant speed traveling control unit 130 corresponding to the shift control unit of the present invention. When the cruise mode is set by the driver operating the cruise control switch 132, the constant speed traveling control means 130 causes the vehicle to travel at a constant speed at the target vehicle speed set together with the setting of the cruise mode. At this time, the constant speed travel control means 130 changes the throttle opening θTH to increase or decrease the engine torque so that the vehicle speed V follows the target vehicle speed VT. When it is difficult to make the vehicle speed V follow the target vehicle speed VT only by changing the throttle opening θTH, the use of some high-speed gears of the automatic transmission 16 is prohibited. In other words, in order to increase the driving force of the vehicle or the engine braking force, the use of the high-speed side gear stage including the currently running gear stage is prohibited to lower the gear stage used and the vehicle speed to the target vehicle speed. Try to follow. Therefore, it can be said that the constant speed traveling control means 130 also constitutes a part of the control device for the automatic transmission.

  When the cruise mode is set, the constant speed traveling control means 130 immediately ends the cruise mode when it is detected by the brake operation determination means 144 described later that the brake operation has been performed. That is, the constant speed running control means 130 prohibits the use of some of the high speed gears of the automatic transmission and lowers the gears to be used, but this is released, for example, in the gear shift diagram shown in FIG. As shown, it is returned to the gear position used by the shift control of a normal automatic transmission. This is because the driver's braking operation during traveling in the cruise mode is regarded as the driver's intention to decelerate.

  The uphill / downhill shift control unit includes an uphill / downhill shift control means 134, an up / downhill shift execution means 136, a storage means 138, a gradient value calculation means 140, a brake operation determination means 144, and the like. Based on a signal from the brake switch 70, the brake operation determination means 144 detects the presence or absence of a braking operation by the foot brake pedal 69 that activates a service brake used to brake the front and rear wheels.

  The gradient value calculating means 140 sequentially calculates values related to the gradient of the road surface on which the vehicle travels. For example, information on the throttle opening θTHN at each vehicle speed V when the vehicle travels on a flat road as shown in FIG. 8 is stored in advance for each shift stage, and the throttle opening at the shift stage during actual travel is shown. The degree θTH and the vehicle speed V are detected by the throttle opening sensor 64 and the vehicle speed sensor 66, respectively, and the throttle opening θTHN when traveling on a flat road at the detected vehicle speed V is compared with the actual throttle opening θTH. For example, if the actual throttle opening degree θTH is within 5% before and after the throttle opening degree θTHN when traveling on a flat road (if it is in the shaded area in FIG. 8), it is determined that the road is a flat road. On the other hand, if it is further away, it is determined that there is a gradient. At this time, when the actual throttle opening θTH is larger than the throttle opening θTHN when traveling on a flat road (when it is above the shaded area in FIG. 8), the actual uphill road, If the throttle opening θTH of the vehicle is smaller than the throttle opening θTHN when traveling on a flat road (if it is below the hatched area in FIG. 8), it is determined that the road is a downhill road. It is judged that the gradient is steeper as the difference between is larger. Specifically, for example, it is determined by calculating in advance and storing the relationship between the magnitude of the difference between the actual throttle opening θTH and the throttle opening θTHN when traveling on a flat road and the value related to the actual gradient. . Further, the value related to the gradient is an angle expressed by the unit rad, for example, that the road surface is horizontal.

  The gradient value calculation means 140 is executed in an area where the uphill / downhill shift control means 134 is not executed. That is, the value (gradient value) relating to the road surface gradient calculated by the gradient value calculating means 140 is used for the execution of the uphill / downhill shift control means 134 by the uphill / downhill shift execution means 136 described later. This is because it need not be executed during the execution of the means 134. Therefore, the gradient value calculating means 140 is executed even while the constant speed traveling control means 130 is being executed, but the gradient value calculating means 140 itself does not perform the shift control of the automatic transmission, but the constant speed traveling control. Since they do not interfere with the control by the means 130, both can be executed simultaneously.

  The storage unit 138 stores values related to the gradient sequentially calculated by the gradient value calculating unit 140, for example, for a predetermined period. The gradient value stored in the storage unit 138 is used when an uphill / downhill shift execution unit 136 described later is executed. The predetermined period is, for example, a period until a gradient value is newly calculated by the gradient value calculation unit 140.

  The uphill / downhill shift control means 134 is a case where it is determined by the gradient value calculated by the gradient value calculation means 140 that the vehicle is descending a road surface having a steeper slope than a predetermined value. When the brake operation determination means 144 determines that the driver has operated the foot brake pedal 69, the use of some high speed stages of the automatic transmission 16 is prohibited. That is, by prohibiting the use of some high speed stages of the automatic transmission 16, it is possible to prevent engine brake force or torque (driving force) shortage when traveling downhill.

  The uphill / downhill shift execution means 136 is under the shift control by the constant speed traveling control means 130 corresponding to the shift control means, which is one of the control start conditions by the uphill / downhill shift control means 134, and by the brake operation determination means 144. When it was detected that the foot brake pedal 69 was operated, the gradient value calculating means 140 calculated immediately before the brake operation determining means 144 determined that the brake operation had been performed, and the storage means 138 stored it. Using the value as a value used to determine the gradient of the road surface on which the vehicle is traveling, the up / down hill shift control means 134 determines whether to perform up / down hill shift control.

  In other words, the control by the uphill / downhill shift control means 134 alone has detected that the foot brake pedal 69 is operated while the vehicle is traveling on the downhill road while the uphill / downhill shift control means 134 is being executed. Thus, the slope value calculating means 140 executes the downhill control immediately before it is detected by the uphill / downhill shift execution means 136 that the foot brake pedal 69 is operated, that is, before the start of the uphill / downhill shift means 134. It is determined whether to perform the uphill / downhill shift control using the value calculated and stored in the storage unit 138. As a result, the shift control of the automatic transmission 16 by the uphill / downhill shift control can be performed immediately after the execution of the up / downhill shift control means 134.

  FIG. 9 is a flowchart for explaining a main part of the control operation of the electronic control unit 90. The operation of the automatic transmission control device 90 of the present invention will be described below for each step of this flowchart. In step SA1 corresponding to the constant speed traveling control means 130 that is the speed change control means (hereinafter, “step” is omitted), it is determined whether or not the cruise mode is set by operating the cruise control switch 132 by the driver. Is judged. If this determination is affirmed, the steps after SA2 are executed assuming that the automatic transmission 16 of the vehicle is traveling in the so-called cruise mode, which is controlled by the constant speed traveling control means 130. On the other hand, if this determination is negative, a normal automatic shift is performed, for example, according to the shift diagram shown in FIG. 6, and it is not necessary to apply the automatic transmission control device of the present invention. The flowchart is terminated.

  In SA2 corresponding to the gradient value calculating means 140 and the storage means 138, a value related to the road surface gradient of the vehicle traveling in the cruise mode is calculated and stored. At this time, it is determined whether or not the cruise mode has been canceled in SA5, which will be described later, and if it is determined that the cruise mode has not been canceled, the steps SA2 to SA4 are repeated again, but stored in SA2. It is sufficient that at least one iteration is stored as the value regarding the slope of the road surface. (If SA2 is executed by the next iteration, the new value is stored and the previous value may be discarded.)

  The subsequent SA3 and SA4 correspond to the constant speed traveling control means 130. In SA3, when the constant speed traveling control means 130 makes the vehicle travel at a constant speed at the set vehicle speed VT set by the cruise control switch 132, it is determined whether or not the vehicle can be controlled only by adjusting the throttle opening θTH. If it is determined that sufficient control cannot be performed only by adjustment based on the opening θTH, SA4 is executed. On the other hand, when it is determined that sufficient control can be performed only with the throttle opening θTH, SA5 is executed without executing SA4.

  In SA4, when the constant speed traveling control means 130 causes the vehicle to travel at a constant vehicle speed VT set by the cruise control switch 132, it is determined that a sufficient vehicle speed cannot be maintained only by adjusting the throttle opening θTH. In this case, the gear stage of the automatic transmission 16 is lowered by one stage and the driving force is increased.

  In SA5 corresponding to the constant speed traveling control means 130, it is determined whether the cruise mode has been canceled when the brake operation by the driver is determined by the brake operation determining means 144. The cruise mode is canceled by the driver's operation of the cruise control switch 132 or the foot brake pedal 69. In this step, however, the determination is affirmed only when the driver releases the cruise mode by the operation of the foot brake pedal 69. On the other hand, when it is canceled by other methods or when it is not canceled, the process returns to SA2, and the steps SA2 to SA5 are repeated again.

  In SA6 corresponding to the uphill / downhill shift execution means 136 and the uphill / downhill shift control means 134, it is determined whether or not downhill control needs to be performed immediately after the cruise mode is canceled in SA5. Specifically, immediately before the brake operation determined to be performed in SA5, the road gradient value calculated and stored in SA2 is taken out, and it is determined whether or not the downhill control is performed. . In other words, in the present step, it is determined whether or not the downhill control is performed when the brake operation is performed or based on the slope value of the road surface immediately after. Whether or not the downhill control is performed is determined using the downhill value detected and stored immediately before the start. If the determination is affirmed, the subsequent SA7 is executed. If the determination is negative, the flowchart is terminated as it is.

  SA7 corresponding to the uphill / downhill shift control means 134 is executed when it is determined in SA6 that the downhill control is performed, and the downhill control, that is, the use of the high speed stage of the automatic transmission 16 is prohibited. The Specifically, when the vehicle is traveling at a prohibited shift speed, a downshift is performed so that the shift speed is lower than the prohibited shift speed. When the vehicle is already traveling at the lower gear, shifting up to the prohibited gear is prohibited.

  FIG. 11 is a timing chart showing the transition from the control by the constant speed traveling control means 130 to the control by the uphill / downhill shift control means 136 when the vehicle to which the electronic control unit 90 is applied travels on the downhill road. . In the figure, the numbers surrounded by circles represent changes in the gear positions used.

  At time t11, the vehicle is traveling on the downhill road, and the downhill shift control is executed by the uphill / downhill shift control means 134 that has already been started. As described above, the downhill shift control prohibits the use of some high speed stages of the automatic transmission. At this time, the constant speed running control means 130 which is a shift control means is not executed because the switch is turned off.

  At time t12, the cruise control switch 132 is turned on by the driver, the constant speed traveling control means 130 is executed, and the cruise mode is executed. The constant speed traveling control means 130 controls the throttle opening θTH so that the vehicle speed V follows the target vehicle speed VT. At this time, the constant speed traveling control means 130 and the uphill / downhill shift control means 134 are executed exclusively so that the effects thereof do not interfere with each other. The control means 134 is terminated.

  On the other hand, at the same time as the uphill / downhill shift control means 134 is terminated, the gradient value calculation means 140 is activated. The gradient value calculating means 140 calculates the gradient value of the road surface from the running gear stage, the vehicle speed V, and the throttle opening θTH, and stores it in the storage means 138.

  At time t13, the constant speed traveling control means 130 determines that it is difficult to make the vehicle speed V follow the target vehicle speed VT only by controlling the throttle opening θTH, and in addition to controlling the throttle opening θTH, automatic shifting is performed. Control the machine. Specifically, as described above, downshifting is performed by prohibiting the use of some high speed stages of the automatic transmission. In this timing chart, for example, when the vehicle is traveling at the fourth speed until time t13, the use of the fourth to sixth speeds is prohibited to shift down to the third speed. .

  At time t14, it is determined by the brake operation determination means 144 that the driver has operated the foot brake pedal 69 while the control by the constant speed travel control means 130 is being executed, and the constant speed travel control means 130 is terminated. It is done. On the other hand, in response to this brake operation, the uphill / downhill shift execution means 136 calculates the gradient value calculated by the gradient value calculation means 140 immediately before the driver's brake operation and stored in the storage means 138, and the uphill / downhill shift control means 134. And the uphill / downhill shift control means 134 determines whether to perform downhill control based on the gradient value immediately before the brake operation. At this time, since the gradient value immediately before the brake operation is a value at which the road surface gradient should be subjected to the downhill control, the uphill / downhill shift control means 134 performs the downhill control using the brake operation at time t14 as a start condition. This is determined and executed. Here, the content of the downhill control prohibits the use of some high speed stages (for example, the fifth to sixth speed stages) of the automatic transmission 16.

  The determination by the uphill / downhill shift control means 134 is completed before the prohibition of the prohibition of use of the high speed stage (the fourth speed stage to the sixth speed stage) is executed in response to the end of the constant speed traveling control means 130. Thus, at the time t14, the third speed stage based on the control by the constant speed traveling control means 130 can be shifted to the fourth speed stage based on the downhill control by the uphill / downhill shift control means 134. That is, as in the case of t3 to t5 in FIG. 10, the use of all the gears is temporarily prohibited based on the end of the control by the constant speed traveling control means 130, and after going to the high speed, the uphill / downhill shift control is performed. Downhill control by means 134 is started and a downshift is performed, so that hunting of the gear stage (speed ratio) does not occur.

  According to the present embodiment, in the automatic transmission 16, the gradient value calculating unit 140 calculates and stores it by the storage unit 138 even immediately after releasing the control by the constant speed traveling control unit 130 by the brake operation during traveling on the uphill / downhill road. Since the uphill / downhill shift control means 134 is executed by the uphill / downhill shift execution means 136 using the value relating to the road surface gradient immediately before the brake operation, the uphill / downhill shift control can be performed even immediately after the brake operation. Thus, it is possible to smoothly shift to the uphill / downhill shift control after the brake operation and to continuously perform the control prohibiting the shift of the gear ratio to the high speed side, thereby preventing the gear ratio hunting.

  Further, according to the present embodiment, even when the control by the uphill / downhill shift control means 134 is performed immediately after the control by the constant speed travel control means 130 for constant speed travel is released by the brake operation, the control is smoothly performed. Shift to uphill / downhill shift control can be performed, and control for prohibiting shift to the high speed side of the gear ratio can be continuously performed, so that hunting of the gear ratio can be prevented.

  Further, according to the present embodiment, the brake operation by the driver is both an operation for releasing the control by the constant speed traveling control means 130 and an operation for starting the control by the downhill shift control means 136. On downhill roads where applicable, downhill gearshift control is performed using values related to the road surface gradient immediately before brake operation even immediately after the shift control is canceled during braking on downhill roads. Shift to slope shift control can be performed, and control for prohibiting shift to the high speed side of the gear ratio can be performed continuously, so that hunting of the gear ratio can be prevented.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, although the stepped automatic transmission as shown in FIG. 1 is used as the automatic transmission 16 in this embodiment, the present invention is not limited to this. For example, a belt type continuously variable transmission, a toroidal continuously variable transmission, and the like. It may be a continuously variable transmission (CVT). In this case, in the embodiments, the descriptions of “increasing the gear position” and “decreasing the gear position” may be read as “decreasing the gear ratio” and “increasing the gear ratio”, respectively.

  In the above-described embodiment, the shift lever 72 is of a type called a so-called floor shift as shown in FIG. 4, but is not limited to this, and is arranged to support the handle, for example. What is called a column shift provided in a steering column part may be used.

  Moreover, although the case where the vehicle travels on a downhill road is illustrated in the above-described embodiment, the present invention can be similarly applied even when the vehicle travels on an uphill road. On the uphill road, the uphill / downhill shift control means 134 determines that the vehicle is climbing a road surface having a steeper slope than a predetermined value based on the slope value calculated by the slope value calculation means 140, for example. This is executed when it is determined by the brake operation determination means 144 that there has been a so-called kick-down operation in which the driver performs a rapid accelerator operation and the gear position of the automatic transmission is lowered by one step. Therefore, for example, the case where the climbing control is started by kick-down immediately after the cruise mode is canceled by the brake operation by the driver during the cruise mode is applicable.

  Further, in the above-described embodiment, as the value related to the road surface gradient, the value representing the road surface gradient as an angle is used as the gradient value. However, the value is not limited to this value. It is good also as a value about.

  Moreover, in SA2 in the above-mentioned flowchart, the gradient value stored is one iteration, but is not limited to this, and a plurality of values may be stored. In this case, in SA6, it can also be determined whether or not to perform downhill shift control based on the plurality of stored gradient values.

  Further, in SA4, when it is determined that the vehicle speed cannot be sufficiently maintained only by adjusting the throttle opening θTH, the shift stage of the automatic transmission 16 is lowered by one stage. Is not limited to one stage, and may be a plurality of stages as necessary.

  In this embodiment, the constant speed running control means is the speed change control means. However, the automatic speed ratio is prohibited from being higher than the predetermined speed ratio, and the control is canceled when a brake operation is performed. However, the control means is not limited to this as long as the control means has such a property.

  In the present embodiment, the gradient value calculation means 140 is calculated from the gear stage used by the vehicle, the vehicle speed, and the throttle opening, but is not limited to this, and may be another method such as an acceleration sensor.

It is a skeleton diagram explaining a power transmission device including an automatic transmission to which the present invention is applied. FIG. 2 is a diagram illustrating engagement and disengagement states of clutches and brakes for establishing each gear stage of the automatic transmission of FIG. 1. It is a figure explaining the input-output signal of the electronic control apparatus provided in the vehicle of the Example of FIG. It is a perspective view which shows the shift lever of FIG. 3 concretely. It is a figure which shows an example of the relationship between the throttle opening Acc used by throttle control performed by the electronic controller of FIG. 3, and throttle valve opening (theta) TH. It is a figure which shows an example of the shift map (map) used by the shift control of the automatic transmission performed by the electronic controller of FIG. It is a functional block diagram explaining the principal part of the control function with which the electronic control apparatus of FIG. 3 is provided. It is the figure explaining the calculation method of the gradient in the gradient calculation means of FIG. FIG. 4 is a flowchart for explaining an operation of a main part of a control function of the electronic control device of FIG. 3, that is, an operation of a control device for an automatic transmission provided in a vehicle. 7 is a timing chart showing a state of transition from control by a constant speed traveling control means, which is a shift control means, to control by an uphill / downhill shift control means during traveling on a downhill road of a vehicle in the prior art. 6 is a timing chart showing a transition from control by constant speed traveling control means, which is shift control means, to control by uphill / downhill shift control means during traveling on a downhill road of the vehicle when the present invention is applied.

Explanation of symbols

16: Automatic transmission 90: Automatic transmission control device 130: Shift control means (constant speed running control means)
134: Uphill / downhill shift control means 136: Uphill / downhill shift execution means 140: Gradient value calculation means 144: Brake operation determination means

Claims (3)

Shift control means for prohibiting the gear ratio of the automatic transmission from becoming higher than a predetermined gear ratio, and releasing the control when there is a service brake operation;
In a control device for an automatic transmission for a vehicle, comprising an uphill / downhill shift control means for prohibiting a speed ratio of the automatic transmission from becoming higher than a predetermined speed ratio based on a value related to a slope of a road surface while traveling on an uphill / downhill road ,
A gradient value calculating means for calculating a value related to the gradient of the road surface;
Brake operation determining means for determining presence or absence of the brake operation;
When the shift control is being performed by the shift control unit and the brake operation is determined by the brake operation determining unit, a value relating to the road gradient immediately before the brake operation determination is output to the up / down slope shift control unit, and the up / down slope shift control is performed. A control device for an automatic transmission for a vehicle, comprising: uphill / downhill shift execution means for executing The automatic transmission for a vehicle according to claim 1, wherein the shift control means is a constant speed traveling control means for controlling a gear ratio of the automatic transmission so as to maintain a constant speed traveling of the vehicle. Control device. The uphill / downhill shift control means is a downhill shift control means for prohibiting the speed ratio of the automatic transmission from becoming higher than a predetermined speed ratio based on a value relating to the slope of the road surface particularly during downhill travel. The control device for a vehicle transmission according to claim 1 or 2.

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